i CUTANEOUS SENSIBILITY 49 



considered as a special modality of cutaneous sensation (as held 

 by Brown-Sequard, Funke, Mlinsterberg). We have already 

 seen that the more recent work of v. Frey and Kiesow is decidedly 

 in favour of this view, and must now investigate the arguments 

 on which it is founded. 



Funke (1880) was the first to call the attention of physio- 

 logists to the interesting clinical observation that a dissociated 

 paralysis of pain sensibility is possible while other specific modal- 

 ities of cutaneous sensation remain normal. Special forms of 

 dissociation of the different forms of cutaneous sensibility have 

 been described since Weber's time in a number of cases of spinal 

 disease (spinal compressions, traumatic spinal lesions, syringo- 

 myelia, tabes dor sails, etc.) Analgesia with integrity of sensi- 

 bility to contact, cold, .and heat is not uncommon ; it not merely 

 involves the skin, but may also extend to the deeper tissues, the 

 muscles, the bones, and the mucous membrane. The case cited 

 by Weber of the Swiss physician Viessaux (1818) deserves 

 mention. He was attacked by spinal disease, and noticed with 

 surprise that the fingers of his right hand could be wounded or 

 crushed without producing any pain, although he was able to 

 detect all the' clinical characters of the pulse with them. In this 

 case of dissociation of cutaneous sensations the post-mortem 

 examination showed a lesion confined to the dorsal horn of the 

 spinal grey matter, which agrees with the view of Schiff and 

 Budge. 



How is such isolated analgesia to be explained, if we assume 

 that the peripheral and central organs for pain sensibility are the 

 same that subserve tactile and thermal sensations ? As Funke 

 correctly remarks, it would be paradoxical to assume that those 

 peripheral and central organs which subserve tactile, thermal, and 

 pain sensibility could become inexcitable to the strong stimuli 

 that are necessary to induce pain, and at the same time preserve 

 their excitability to the slight stimuli that suffice to produce 

 tactile and thermal sensations. To account for the phenomenon 

 of isolated analgesia it is necessary to admit either that from the 

 spinal cord up to the brain the pain paths are separated from the 

 tactile or thermal paths, as assumed by Schiff, or that the former 

 are already distinct from the latter at the periphery, and that the 

 skin contains specific nerve-endings for pain, 'other than those 

 for tactile and thermal sensibility. Funke leaves the question 

 open. 



In his investigations with point stimulation, Blix observed 

 that every here and there the point of a needle could be pushed 

 deep into the skin without producing the least sensation of pain, 

 while in other parts a slight prick with the needle did cause 

 pain. But his investigations into pain sensibility did not furnish 

 facts to justify the assumption of pain sense-organs anatomically 



VOL. IV E 



